Antihypertensive efficacy of slow-release metoprolol and chlorthalidone as fixed combination: A randomized double blind comparison with chlorthalidone

A randomized between-patient, double-blind comparison between chlorthalidone 25 mg and a fixed combination of slow-release metoprolol 200 mg + chlorthalidone 25 mg was carried out in 30 out-patients with mild-to-moderate essential hypertension. Either agent was given once daily for 6 weeks, after a 2-week placebo period. Patients were in WHO stage 1 or 2, with lying diastolic blood pressure above 95 mmHg after 2 weeks of placebo washout. Lying systolic and diastolic blood pressure decreased, on average, by 15 mmHg and 13 mmHg, respectively, on chlorthalidone, and by 20 mmHg and 13 mmHg, respectively, on the fixed combination of chlorthalidone with slow-release metoprolol. Standing systolic and diastolic blood pressure decreased, on average, by 18 mmHg and 15 mmHg on chlorthalidone, and by 23 mmHg and 20 mmHg on the diuretic-betablocker combination. A satisfactory blood pressure control was achieved by both agents. However, the fixed combination of slow-release metoprolol and chlorthalidone proved to be more effective than chlorthalidone alone on lying diastolic and standing systolic and diastolic blood pressure (P <0.05). In addition, only the fixed combination induced a decrease in the heart rate (P <0.05). Tolerability of either treatment was good; spontaneously reported unwanted effects were of mild severity. In conclusion, this new fixed combination of slow-release metoprolol 200 mg + chlorthalidone 25 mg is effective in the once-daily treatment of arterial hypertension. It is more effective than chlorthalidone used alone and it is devoid of noticeable unwanted effects.